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Activity sampling studies generally run for a number of days and should be configured to be unobtrusive. Activity Logging studies can often be completed in a few hours and therefore minimize disruptions as staff know it’s just a temporary task.

In activity sampling the prompts made to each study participant occur at random times but you configure how many will occur in each hour. A typical frequency would be about three times per hour. Such a frequency has been found to be unobtrusive and easily maintainable. Data entry on the part of the participant should take only a few seconds as they just make their selections from simple drop down lists.

It is however highly unlikely, and indeed unreasonable to expect that participants will be able to respond to every prompt. Profit Profiler will record prompts that are not responded as being missed. A good transaction rate of 80% is reasonable to expect based on our historical data.

In activity sampling therefore the formula for how the number of days required to get results is as follows:

Examples

12 people, 8 hours a day,

3 transactions per hour,

1800 transactions required

= (1800 x (100/80)) / (3x8x12))

= 2250 / 288

= 7.81 days

30 people, 8 hours a day,

3 transactions per hour,

4000 transactions required

=(4000 x (100/80)) / (3x8x30))

= 5000 / 720

= 6.9 days

100 people, 8 hours a day,

2 transactions per hour,

4000 transactions required

=(4000 x (100/80)) / (2x8x100))

= 5000 / 1600

= 3.1 days

Notice in Example 3 we reduced the number of samples per hour. This would be justified if all 100 participants basically performed the same functions. If there were a number of different jobs covered by the participants you may decide to keep the rate at 3 per hour and increase the desired transactions required.

In Activity Logging assume you are looking for 100 transactions for each task. This will allow a reasonable percentage of non typical i.e. “other” transaction and still give you acceptable accuracy. The formula for how many hours it will take to get results is as follows:

Examples

12 primary tasks,

6 transactions per hour and

20 people

= 12 x 100/(6*20)

= 1200 / 120

= 10 hours

30 primary tasks,

8 transactions per hour and

50 people

= 30 x 100 / (8x50)

= 3000 / 400

= 7.5 hours

8 primary tasks,

15 transactions per hour, 10 people

= 8 x 100 / (15x10)

= 800 / 150

= 5.33 hours

8 primary tasks,

15 transactions per hour,

20 people

(i.e. the same as example 3 but with twice the staff

= 8 x 100 / (15x20)

= 800/300

= 2.66 hours

As these results indicate accurate results in Activity Logging can often be obtained in a few hours.